Both in the case of engine valves and in the case, for example, of piston pumps that are used as high-pressure fuel pumps for the pumping of fuel, a rod is commonly provided which is driven by a plunger. The plunger itself is driven, for example in the case of a piston pump as a high-pressure fuel pump, by a camshaft of an internal combustion engine.
FIG. 12 shows a diagrammatic illustration of a rod 12 that is driven by a plunger 10. The arrangement illustrated in FIG. 12 may be used both in, for example, a piston pump 14 as a high-pressure fuel pump 16 and in engine valves 18. In both cases, high-pressure fuel pump 16 and engine valve 18, a movement of the rod 12, which in the case of the piston pump 14 constitutes a piston 20, influences a pressure in a space (not illustrated) which is arranged above the piston 20 in FIG. 12 and which is situated at a first end region 22 of the rod 12.
In the case of the piston pump 14, fuel is pressurized by way of the movement of the piston 20 along a piston axis 24.
In the case of an engine valve 18, the movement of the rod 12 along a rod axis 26 causes the engine valve 18 to be opened and closed, and thus, upon opening, a pressure is discharged, and upon closing of the engine valve 18, pressure is built up. Altogether, therefore, the arrangement shown in FIG. 12 constitutes a pressure-influencing device 28 both in the case of use in a piston pump 14 and in the case of use in an engine valve 18.
The pressure-influencing device 28 in FIG. 12 has a rod guide 30 for guiding the rod 12 and has a plunger guide 32 for guiding the plunger 10. The plunger 10 is constructed from a plunger skirt 34 and a traverse 36, and the traverse 36 is in contact, by way of the plunger skirt 34, with a roller 38. A camshaft moves the roller 38 upward and downward along a plunger guide axis 50, which in FIG. 12 coincides with the rod guide axis 52, wherein the roller 38 transmits said upward and downward movement to the traverse 36. The traverse 36 is in turn in contact with the rod 12 at a second end region 42 of the rod 12, and transmits the upward and downward movement to the rod 12, such that the latter can, by way of its first end region 22, influence a pressure in a space (not shown) arranged above the first end region 22 of the rod 12.
Also schematically illustrated in FIG. 12 is a flange 44, by way of which the pressure-influencing device 28 can be fastened for example to an engine housing.